It is known that most of the alimentary plants are of seasonal character and the ripening period of some fruits and vegetables is relatively short.
This results in the following drawbacks:
original, fresh fruits or vegetables are available only during a relatively short period of the year, PA0 the available processing capacity may not allow the complete utilization of the crop whereby a significant proportion is lost or is utilized in a less valuable manner (e.g. for distilling or for the preparation of fodders from fruits or vegetables), and the transfer of large amounts of biologically ripe fruits over long distances can be achieved only with high costs, if at all, and frequently with deterioration of the quality. PA0 1) the fruits or vegetables, respectively are purified, digested and preserved by alcohol, PA0 2) the preserved material is stored for the time desired, PA0 3) alcohol is removed from the stored alcoholic fruits and/or vegetables by flash distillation under reduced pressure in a dynamical CO.sub.2 and/or inert gas atmosphere, PA0 4) and optionally, the product is processed to the desired product by using a known technological procedure of the food industry or is incorporated into the desired product. PA0 Type I: Fruits and vegetables rich in juice, such as morello, cherry, raspberry, red currant, gooseberry, grape, apricot, peach and the like as well as e.g. tomato. From these fruits and vegetables a fibrous juice is obtained after crushing by pressing. The juice obtained is directly introduced into the storage vessel where it is mixed with alcohol to adjust the alcohol content of the mixture to a value between 15 and 45% by volume. Under the effect of alcohol the digestion completely proceeds by diffusion within a few weeks; heating or cooling is unneccessary. The solid and liquid phases of the alcoholic mixture are well separated; they are easy to separate by a simple racking. PA0 Type II: Apple, pear and other fruits containing less juice, and vegetables such as carrot, beetroot, celery, squash, cucumber, garlic, onion, paprika and the like. Here, the digestion is preceded by a physical grinding. The ground and crushed material is soaked in alcohol and macerated to promote the digestion; if desired, a digestion-promoting, e.g. pectin-decomposing enzyme is used before adding alcohol. During the above operation, the soluble components of the fruits or vegetable are dissolved within a short period whereas a high percentage of the solid parts is broken down. In this case the separation of the macerate has to be accelerated by using e.g. a suitable press. PA0 1. Feed tank with introduction of CO.sub.2 and/or inert gas PA0 2. Pre-heating and film-distilling equipment PA0 3. Head product receiving trap PA0 4. Vacuum pump PA0 5. Inlets for CO.sub.2 and/or inert gas PA0 6. Cooled trap for receiving the product PA0 7. Valves PA0 a) If desired, the juice of vegetables or fruit obtained as bottom product may be processed to jelly, drinking juice or natural flavoring in a known manner. In the preparation of the drinking juice a 0 to 10-fold dilution is used. PA0 b) If desired, the juice of fruit or vegetables containing 30 to 51% by volume of alcohol obtained as head product may further be refined up to an alcohol concentration of 60 to 80% by volume in the distilling equipment according to the demands. This fraction with a high alcohol content may be recycled into the preservation procedure and again utilized for the preservation of fresh plant material. (It should be noted that the recycled alcohol can be used for preserving only the same fruit from which it has been separated since a small part of the flavor components is present in this fraction.) PA0 it can be used within a practically unlimited scope of fruits and vegetables, PA0 the plant material can be stored for a practically unlimited period, PA0 the alcohol can be removed from the material stored simultaneously with the complete retention of the flavors, colors and other valuable ingredients, PA0 the obtained product ready for consumption does not contain any preserving agent, PA0 due to the nearly complete removal of alcohol, the product obtained can widely be utilized, and PA0 the alcohol distilled out from the stored product may be used as alimentary substance or recycled in the process whereby the economy of the process can be improved.
The recently available processing methods offer to the researchers several tasks to be solved. e.g. one of the highest difficulties of preparing juices of natural raw material and other food compositions obtained from various fruits is that, in most cases, a long interval elapses up to the processing of the harvested fruits and bottling of the juice. During this period the protection of the fruit against microorganisms and inhibition of its native enzyme system should be ensured in a manner providing the most complete maintenance of nutritive ingredients and flavor substances of the freshly harvested fruits. According to the present practice, two methods are used, for accomplishing this task, however, these methods are expensive and are not fully satisfactory.
1) chemical preservation of the must is typically achieved by adding to the product 1000 to 1200 mg/liter of free sulfurous acid and storing product until the further processing.
The sulfurous acid provides a real protection against microorganisms which, however, does not last for a long time since the acid becomes bound and has to be supplemented for maintaining its effect from time to time. According to the observations, the flavoring (aromatizing) materials are also damaged by sulfurous acid, particularly when the must stored is concentrated for the further processing. Due to the required long-lasting heat effect, in addition to the heat-decomposition of a part of the natural flavor substances, sulfur-containing flavor substances with an unpleasant taste may be formed. The health-damaging effect of sulfurous acid is also well-known.
2) Pasteurizing, another widely used method of preservation, does not fulfill all requirements either: The costs and the power demand of the equipment are high; the heat-effect used causes the loss of a part of flavor substances and eventually the occurrence of unpleasant flavor substances. It is particularly to be emphasized that heat-sensitive vitamins are decomposed during pasteurizing and thus, in addition, the biological value of the composition is also deteriorated together with the organoleptic value.
The problem discussed above is valid to a greater or lesser degree also in the processing of vegetables. The preservation of tomato can be mentioned as an example.
Ethanol has been used as an ideal preserving agent e.g. in the liquor industry since ancient times. The fruit compositions thus preserved are incorporated in alcoholic drinks. Ethanol is an optimal preserving agent due not only to its persistent action but also to the formation of various fruit esters enriching the original flavors of the fruits.
This method of preservation, however, cannot be used widely because, due to its alcohol content, the utilization of the preserved plant material stabilized by ethanol is possible only in a limited range of food materials.